WO2004033787A2

WO2004033787A2 - Cellulose material with enhanced fire resistance

Info

Publication number: WO2004033787A2
Application number: PCT/FR2003/002994
Authority: WO
Inventors: Michel Lagrenee; Fouad Bentiss; Jean-François HENETTE; Didier Delval
Original assignee: Carbocia
Priority date: 2002-10-10
Filing date: 2003-10-10
Publication date: 2004-04-22
Also published as: FR2845699A1; AU2003300485A8; WO2004033787A3; FR2845699B1; AU2003300485A1

Abstract

The invention concerns a cellulose material having enhanced fire resistance, comprising, covalently bound to its cellulose structure, a polymer having the following structural unit: (A), partly substituted by dehydroxyphosphoryl groups, said covalent bond being in particular obtained by reacting urea. The method for preparing said cellulose material with enhanced fire resistance consists in: a) preparing a water-soluble polymer having the structural unit (A), partly substituted by dehydroxyphosphoryl groups, b) optionally mixing said polymer with urea, c) contacting said polymer or said mixture with the cellulose material, d) bringing the whole resulting product to a temperature ranging between 140 and 180 °C.

Description

CELLULOSIC MATERIAL WITH IMPROVED FIRE RESISTANCE

The present invention relates to a cellulosic material whose fire resistance has been improved by the introduction into its macromolecular structure of a polymer with a flame retardant character. It also relates to a treatment method allowing the introduction of this polymer into the macromolecular cellulosic structure.

In this text, we will talk about cellulosic material. This term is used to designate a material which comprises in its macromolecular structure cellulosic chains, in whole or in part. It can especially be in the textile field of natural cellulosic fibers such as cotton, linen or hemp or of artificial cellulosic fibers such as viscose, cellulose acetate, cellulose triacetate, polynosic fibers, etc. It can also s 'act of a cellulosic material other than textile, in particular lignocellulosic fiber in the field of paper or particle board.

The above list is not exhaustive, however. In the fields where cellulosic materials are the most used, in particular clothing, furniture, construction, we seek to reduce the flammable nature of cellulose by performing flame retardant treatments. In particular, with regard to the textile field, it has already been proposed to use organophosphoric compounds for obtaining a flame retardant finish. For example, in document FR 2 046 777, the cellulosic fibrous material is treated with aqueous impregnation baths which contain phosphoric esters containing N-hydroxymethyl groups and corresponding to the general formula O CH ₂ OH

O = P - (CH2) _n -O-CO-N ^ R'O Y in which R and R 'each represent an al yl residue lower, n denoting a number from 1 to 4 and Y a hydrogen atom or the remainder -CH ₂ OH, then the fibrous material thus impregnated is subjected to a heat treatment.

In document FR 2 094 185, the aqueous flame retardant preparation contains a reaction product obtained by condensing an N-methylolamide free of water and having the formula: R, -O _\ ^ =

R, -O -CH, -CO-NH-CH, OH in which R and R ₂ each denote an alkyl, haloalkyl or alkenyl residue having 1 to 4 carbon atoms, in an anhydrous medium, the product being condensed on it -same and the condensation prolonged until for one mole of N-methylolamide used, the separation of about 0.7 to 1 mole of water is obtained. The dried textile material is then subjected to a treatment at high temperature.

Finally, in document FR 2 152 696, a water-soluble condensation product is used as the flame retardant, consisting of one mole of a tetrakis- (hydroxy-methyl) -phosphonium compound and 0.02 to 1 mole of methylolated urea or its alkyl ether.

Thus, it is known to use compounds for the fireproofing of cellulosic material comprising phosphorus atoms and nitrogen atoms.

The subject of the present invention is a cellulosic material having improved fire resistance and which comprises, linked by covalent bond to its cellulosic structure, a polymer having the following unitary units:

partially substituted by dehydroxyphosphoryl groups.

On the one hand, because of the covalent bond, the flame retardancy is maintained after washing and on the other hand, this fire resistance is significantly improved compared to what is currently known, probably due to the interaction, in each unitary motif, of components which are moreover already known to provide a certain flame-retardant character.

The covalent bond between the polymer and the cellulosic structure can be obtained by involving an esterification reaction of a phosphonic acid (of a hydroxy phosphoryl group) on a hydroxyl group of the cellulose.

The covalent bond between the polymer and the cellulosic structure can be obtained by reacting urea. Preferably m = 1 or 2.

The number n of unitary units of the polymer is variable; it can be 2 and also greater than 50. Its average value is around 9.

It is another object of the present invention to provide a process for the preparation of a cellulosic material with improved fire resistance, as described above. This process consists: a) in preparing a water-soluble polymer having the unitary unit:

partially substituted by dehydroxyphosphoryl groups.

b) optionally mixing this polymer with urea, c) bringing said water-soluble polymer or said mixture into contact with the cellulosic material, d) bringing the assembly to a temperature between 140 and 180 ° C.

When it is a cellulosic material of a textile nature, preferably the water-soluble polymer or the mixture of polymer and urea is dissolved in an aqueous treatment bath and the contacting of the cellulosic material with the water-soluble polymer or the mixing is done by impregnating said material with said treatment bath.

The polymer having the abovementioned unitary unit is made soluble in an aqueous medium by acidification of the phosphoric acid supplied in the form of ammonium phosphate. This salification reaction forms pyro or polyphosphates which allow the partial substitution of the polymer by hydroxyphosphoryl groups, as follows: The polymer having the above unitary unit is made soluble in aqueous medium by acidification of phosphoric acid supplied in the form of ammonium phosphate. This salification reaction forms pyro or polyphosphates which allow the partial substitution of the polymer by dehydroxyphosphoryl groups, as follows: OH

H 0 = P = O

- C - N - C -

NH O

For the preparation of the water-soluble polymer having the aforementioned unitary unit, different routes are possible, either at atmospheric pressure, or in a reactor closed under pressure. Among these routes, mention may be made, with regard to the polymer in which m = 1: thermal decomposition of guanylurea in the form of phosphate, alone or in urea, in the presence of ammonium phosphate,

Reaction of guanylurea in the form of phosphate in urea in the presence of phosphoric, pyrophosphoric or polyphosphoric acid followed by heating with an ammonia solution, - Reaction of guanidine in the form of phosphates or carbonate in urea in presence of ammonium phospates (mono, di or triammonic),

Reaction of guanidine in the form of phosphates or carbonate in urea in the presence of phosphoric, pyrophosphoric or polyphosphoric acid followed by heating with an ammonia solution,

Heating until guanylurea hydrochloride melts, washing with water then treatment with pyro or polyphosphoric acid followed by heating with an ammonia solution.

Guanidine reaction in the form of phosphates or of carbonate on urethane in the presence of ammonium phosphates.

Reaction of guanidine in the form of phosphates or carbonate on urethane in the presence of phosphoric, pyrophosphoric or polyphosphoric acid followed by heating with an ammonia solution.

Heating until the esters of guanidinomethanoic acid (guanoline) are melted in urea in the presence of ammonium phosphates, - Heating until the esters of guanidinomethanoic acid (guanoline) in urea are melted in the presence of phosphoric, pyrophosphoric or polyphosphoric acid followed by heating with an ammonia solution, For the preparation of the water-soluble polymer having the aforementioned unitary unit in which m = 2, different routes are also possible involving the reaction of dicyandiamide on the ammonium phosphate in the presence of urea or urethane. This synthesis can be carried out: - by heating the mixture of the three constituents or prior reaction of dicyandiamide with ammonium phosphate then reaction with urea or urethane; by reaction of biguanide in the form of phosphate in urea in the presence of ammonium phosphates

(mono, bi or triammonic); by reaction of biguanide in the form of phosphates in urea in the presence of phosphoric, pyrophosphoric or polyphosphoric acid followed by heating with an ammonia solution.

Among all these possible routes, are described more fully some nonlimiting examples making it possible to prepare the water-soluble polymer having the aforementioned unitary unit.

EXAMPLE 1 90 g of guanidine carbonate, 240 g of urea and 230 g of ammonium dihydrogen phosphate are mixed. The reagents are finely ground to have a homogeneous mixture. The latter is heated in a reactor. The mixture melts between 115 and 120 ° C (about 30 minutes to reach melting) and it is then stirred. There is foaming (allow almost half the volume of the reactor for foam). It is noted that there is release of ammonia and formation of ammonium carbonate on the walls of the refrigerant. After 30 minutes of stirring, the foam disappears and the mixture reaches 140 ° C. The reaction medium is left to react for 3 hours (from melting) at 140 ° C. with stirring. Then, the final product is cooled (to approximately 1 10 ° C) and diluted with an ammoniacal solution (250g of water and 10g NH ₄ OH 30%). The pH of the final product is equal to 9. The mixture is left to stir under reflux for approximately 15 minutes (until the solution becomes clear). Guanidine carbonate can be replaced by mono and biguanidine phosphate by reducing the amount of ammonium phosphates (mono, di or triammonique). EXAMPLE 2 90 g of guanidine carbonate, 240 g of urea and 1 mole of pyrophosphoric acid are mixed. The mixture is heated at 140 ° C for 3 hours. The final product is cooled (to around 100 ° C) and made up to 650g with an ammonia solution. Pyrophosphoric acid can be replaced by an equivalent amount of polyphosphoric acid.

EXAMPLE 3: 84 g of dicyandiamide, 240 g of urea and 230 g of ammonium phosphates (mono, di or triammonic) are mixed. The reagents are finely ground to have a homogeneous mixture. The latter is heated to reflux in a reactor. The mixture melts at around 130 ° C. It is left to react for 3 hours at 140 ° C. with stirring. Then, the final product is cooled (to around 100 ° C), made up to 650g with water and then filtered.

EXAMPLE 4 84 g of dicyandiamide are dissolved in 11 g of phosphoric acid (85%). Then 120g of ammonia, 240g of urea and 1 15g of ammonium phosphate are added. The mixture is heated at 140 ° C for 3 hours after evaporation of the water. The final product is cooled (to around 100 ° C), made up to 650g with water and then filtered.

EXAMPLE 5: 84 g of dicyandiamide, 240 g of urea and 172 g of pyrophosphoric acid are mixed. The mixture is heated at 140 ° C for 3 hours. The final product is cooled (to around 100 ° C), made up to 650g with an ammonia solution and then filtered. Pyrophosphoric acid can be replaced by an equivalent amount of polyphosphoric acid.

EXAMPLE 6 197 g of guanylurea phosphate, 240 g of urea and 230 g of ammonium phosphates (mono, di or triammonic) are mixed. The reagents are finely ground to have a homogeneous mixture. The latter is heated to reflux in a reactor. The mixture melts at around 130 ° C. It is left to react for 3 hours at 140 ° C. with very slow stirring. Then, the final product is cooled (to around 100 ° C) and made up to 650g with water.

EXAMPLE 7 197 g of guanylurea phosphate are dissolved in 58 of phosphoric acid (85%). Then 120g of ammonia, 240g of urea and 58g of ammonium phosphate are added. The mixture is heated at 140 ° C for 3 hours after evaporation of the water. The final product is cooled (to around 100 ° C), made up to 650g with water and then filtered.

EXAMPLE 8 197 g of guanylurea phosphate, 240 g of urea and 86 g of pyrophosphoric acid are mixed. The mixture is heated at 140 ° C for 3 hours. The final product is cooled (to around 100 ° C), made up to 650g with an ammonia solution and then filtered. Pyrophosphoric acid can be replaced by an equivalent amount polyphosphoric acid.

EXAMPLE 9 In a reactor, 84 g of dicyandiamide (DDA), 1 15 g of water and 130 g of 75% phosphoric acid are mixed. DDA and water are put first in the reactor. Then, 60% of the quantity of phosphoric acid is added and the mixture is heated slowly with stirring. Heating is stopped when the temperature reaches 80 ° C. Since this reaction is very exothermic, the temperature will increase to 105-100 ° C. At this temperature, the rest of the phosphoric acid is added very slowly (over 15-20 minutes). When all of the acid is added, the temperature is maintained at 105 ° C for 50 minutes. Then, 125 g of urea is added to the guanylurea phosphate and the mixture is heated with stirring for 10 to 15 minutes at 90 ° C until complete dissolution. Then, slowly add 110g of a 30% ammonia solution (for about 30 minutes). When the addition is complete, the water is evaporated and the mixture is heated at 140 ° C for 3 hours. The final product is cooled and made up to 650g with water.

The final product obtained in all of the above examples is a polymer having the unitary unit characteristic of the present invention with a coefficient m equal to 1 for examples 1 and 2, 6 to 9 and to 2 for examples 3 to 5.

The polymer having the aforementioned unitary unit is water-soluble: it is therefore most generally an aqueous treatment bath containing said polymer and possibly urea which will be used to obtain the cellulosic material with improved fire resistance. This polymer is diluted in water to a concentration which is a function of the desired performance. The treatment bath is preferably brought to a temperature between 50 and 70 ° C to facilitate its impregnation of the cellulosic material.

As it is in particular a cotton canvas, the impregnation is made by passing over the scarf with a double expression, the pressure of the rollers being determined so as to provide an input from the treatment bath of the order of 50% of the weight of the fabric. This is then subjected to a heat treatment, in oar or in polymerizer, at a temperature which is between 140 and 180 ° C. During this heat treatment, the urea reacts on the alcohol functions of the cellulosic structure and on the water-soluble polymer and a fixing of said polymer is therefore obtained by covalent bond on the cellulosic structure. After the heat treatment, it is desirable to carry out a washing of the fabric in order to remove the excess products which are not fixed, for example passing over Jigger in running water at around 40 ° C.

It should be noted that in the routes envisaged above for the production of the water-soluble polymer, urea is used and the polymer is obtained in the dissolved state in an aqueous solution. It is therefore possible to use this solution as a treatment bath provided that excess urea is used so as to find in the treatment bath not only the water-soluble polymer, but also the quantity of urea necessary to produce the fixing of this polymer on the cellulosic structure.

The canvas thus treated with fire retardant, washed and dried, can, quite advantageously, be subjected to a waterproofing treatment by passage through a bath at room temperature consisting of an aqueous solution containing: - 10 to 20 g / l Zirconium acetate,

- 80 to 100 g / l of dicyandiamide formalin,

- 30 to 60 g / l of a fluorinated resin.

This passage is carried out on a scarf with double expression. The fabric thus impregnated is subjected to a heat treatment of the order of 150 ° C.

The presence of Zirconium acetate and dicyandiamide formalin in the waterproofing bath has the advantage of allowing the complete elimination of any traces of phosphate which would remain after washing the fabric, not fixed to the cellulosic structure. Such a fabric with improved fire resistance and waterproofed as described above, can be used in particular as a tarpaulin and as a tent fabric.

Another advantage of the present invention should be emphasized, namely that the claimed cellulosic material also has rot-proofing properties, which is particularly advantageous in the application of this material as a tarpaulin or tent fabric.

In addition, in the case of a textile material, it has also been found that this material has, compared to the same untreated material, better resistance to shrinkage. The present invention is not limited to the only examples which have been described above and which relate to the application of the cellulosic material of the invention to the textile field. In particular, it can be applied in the field of particle boards. In this case, the incorporation of the polymer on the cellulosic structure is carried out, during the manufacture of the particle board, by incorporating the said polymer and the urea in the adhesive which is used for the hot consolidation.

Claims

1. Cellulosic material having improved resistance to fire, characterized in that it comprises, linked by covalent bond to its cellulosic structure, a polymer having the following unitary motif:

NH partially substituted by dehydroxyphosphoryls groups.

2. Cellulosic material according to claim 1 characterized in that the covalent bond between the polymer and the cellulosic structure is obtained by reacting urea.

3. A method of preparing a cellulosic material with improved fire resistance, characterized in that it consists of: a) preparing a water-soluble polymer having the unitary pattern,

partially substituted by dehydroxyphosphoryl groups. b) optionally mixing this polymer with urea, c) bringing said polymer or said mixture into contact with the cellulosic material, d) bringing the assembly to a temperature between 140 and 180 ° C.

4. Method according to claim 3 characterized in that the cellulosic material being of textile nature, the polymer or the mixture of polymer and urea is dissolved in an aqueous treatment bath and the contacting of the cellulosic material with the polymer or the mixture takes place by impregnation of said material with said treatment bath.

5. Process for the preparation of a textile and impermeable cellulosic material with improved fire resistance, characterized in that the material, having undergone the steps of the method of claim 4, is subjected to a waterproofing bath containing acetate of Zirconium and dicyandiamide formalin.

6. Method for preparing a panel of cellulosic particles, in which the cellulosic particles are agglomerated hot by means of glue, characterized in that the glue contains a mixture of urea and a polymer having the following unitary pattern:

partially substituted by dehydroxyphosphoryl groups.